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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

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CHAPTER V
THE GALIANO AND BLACK GLACIERS
GALIANO GLACIEB
General Description. Although small, this is one of the most interesting glaciers of the Yakutat Bay region. It has been known since 1890 when Russell named and described it, and, although it has undergone some remarkable changes in the interval, its .general features are now much as in 1890 (Map 2, in pocket).
Like many other neighboring glaciers, the Galiano consists of two quite different parts, Ľa valley glacier portion and an expanded piedmont bulb beyond the mountain front; but to one unfamiliar with the phenomena of ablation moraines neither the bulb nor the valley portion looks like a glacier, for in all but a few places the ice is obscured from view by thick moraine, bearing alder on the outer portion. The valley which the Galiano Glacier occupies is broad, deep, and cirque-like with steeply-rising walls, and is enclosed in mountains which rise to elevations of 5000 to 6000 feet and bear a heavy cover of snow. From these snowfields several cascading glaciers descend (PI. XXVIII), especially at the very head of the valley, supplying the ice for the glacier and a large part of the morainic debris which coats its surface; but some of this is also supplied by avalanches from the bare rock slopes which have been steepened by glacial erosion. The sound of falling stones is heard every few minutes when one is in this valley.
The cascading tributaries are a mile to a mile and a half long. The valley portion of the glacier is about three miles and the piedmont bulb is three quarters of a mile long, and a mile wide. The breadth of the glacier at the entrance to the mountain valley is three quarters of a mile while in the mountain valley the width is only a little over a quarter mile. With the steeply-rising snow-capped sides and head and the broad lower part, one is greatly deceived in the length of the valley when seen from a distance. It does not appear to be more than a mile or two long. The glacier has a slope from the mouth of the valley to its head of between 10 and 15 degrees. At no time when observed has this glacier been much crevassed, though in 1905 crevassing was observed near the valley head; and where the tributaries entered there were also areas of decided crevassing. Below its crevassed uppermost portion the Galiano Glacier has the appearance of stagnation, an appearance which finds ready explanation in the small size of the contributing glaciers. Indeed, it seems quite remarkable that such a limited ice supply could maintain a glacier of such length and breadth with its lower end nearly at sea level; and it is very doubtful if they could do so were it not for the fact that the wasting of a large part of the glacier is greatly retarded by the moraine cover which it bears.
Just within the mountain valley, on either margin of the glacier, there is a marginal valley with moraine-covered ice for one wall and the mountain rock for the other. In each of these valleys is a marginal stream, that on the west side being much the larger
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